Is there any way to express how close a project is to completion as a percentage? Can the progress bars show that a project is X% complete?

Over the years, we've found that most research teams don't load a certain number of work units into World Community Grid, let them run, and then declare the project complete. Rather, they create work units based on their initial research questions, then make adjustments to future work units based on their findings on World Community Grid and on outside research findings. This makes it impossible to accurately express project completion as a percentage.